Table 4.

Effect of prescribed dietary protein on bias in GFR estimation using the MDRD study equation and the CKD-EPI Cystatin C 2008 study equation.^*

Equation Performance	Timing	Study A (n=302)		Study B (n=124)
Δ Bias eGFRcr (ml/min/1.73 m2)	Baseline	−0.23	[−1.61, 1.15]	−0.35	[−1.75, 1.10]
Δ Bias eGFRcr (ml/min/1.73 m2)	Follow up	−2.77	[−4.08, −1.48]	−1.37	[−2.88, 0.15]
Δ Bias eGFRcys (ml/min/1.73 m2)	Baseline	−0.60	[−2.20, 0.99]	−0.50	[−0.75, 1.76]
Δ Bias eGFRcys (ml/min/1.73 m2)	Follow up	−0.31	[−1.75, 1.13]	−0.02	[−1.70, 1.75]

^*Differences in mean bias between randomized groups (bias in low protein diet group minus bias in usual protein diet group in Study A; very low minus low protein diet group in Study B). Bias is defined as measured-estimated GFR.

All values are reported as mean and 95 % CI. Values highlighted in boldface are statistically significant with p<0.01. p for eGFRcr at follow up in Study B is 0.08.